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.

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.

scholarly journals gerT, a Newly Discovered Germination Gene under the Control of the Sporulation Transcription Factor σK in Bacillus subtilis

2007 ◽  
Vol 189 (21) ◽  
pp. 7681-7689 ◽  
Author(s):  
Caitlin C. Ferguson ◽  
Amy H. Camp ◽  
Richard Losick
Keyword(s):  
Transcription Factor ◽  
Bacillus Subtilis ◽  
Gene Product ◽  
Early Stage ◽  
Dna Binding Protein ◽  
Positive Control ◽  
Negative Control ◽  
Spore Coat ◽  
Morphogenetic Protein ◽  
Two Stages

ABSTRACT We report the identification of a gene, herein designated gerT (formerly yozR), that is involved in germination by spores of Bacillus subtilis. The gerT gene is induced late in sporulation under the positive control of the transcription factor σK and under the negative control of the DNA-binding protein GerE. The gerT gene product (GerT) is a component of the spore coat, and its incorporation into the coat takes place in two stages. GerT initially assembles into foci, which then spread around the developing spore in a process that is dependent on the morphogenetic protein CotE. Mutant spores lacking GerT respond poorly to multiple germinants and are impaired at an early stage of germination.

scholarly journals Searching for Protein-Protein Interactions within the Bacillus subtilis Spore Coat

2009 ◽  
Vol 191 (10) ◽  
pp. 3212-3219 ◽  
Author(s):  
Daniela Krajčíková ◽  
Magda Lukáčová ◽  
Denisa Müllerová ◽  
Simon M. Cutting ◽  
Imrich Barák
Keyword(s):  
Bacillus Subtilis ◽  
Complex Structure ◽  
Insoluble Fraction ◽  
Size Exclusion ◽  
Strong Interactions ◽  
Spore Coat ◽  
Coat Proteins ◽  
Yeast Two Hybrid ◽  
Lytic Enzymes ◽  
Two Hybrid

ABSTRACT The capability of endospores of Bacillus subtilis to withstand extreme environmental conditions is secured by several attributes. One of them, the protein shell that encases the spore and is known as the coat, provides the spore with its characteristic resistance to toxic chemicals, lytic enzymes, and predation by unicellular and multicellular eukaryotes. Despite most of the components of the spore coat having been identified, we have only a vague understanding of how such a complex structure is assembled. Using the yeast two-hybrid system, we attempted to identify direct contacts among the proteins allocated to the insoluble fraction of the spore coat: CotV, CotW, CotX, CotY, and CotZ. We also examined whether they could interact with CotE, one of the most crucial morphogenetic proteins governing outer coat formation and also present in the insoluble fraction. Out of all 21 possible interactions we tested, 4 were found to be positive. Among these interactions, we confirmed the previous observation that CotE forms homo-oligomers. In addition, we observed homotypic interactions of CotY, strong interactions between CotZ and CotY, and relatively weak, yet significant, interactions between CotV and CotW. The results of this yeast two-hybrid analysis were confirmed by size exclusion chromatography of recombinant coat proteins and a pull-down assay.

scholarly journals Morphogenetic Proteins SpoVID and SafA Form a Complex during Assembly of the Bacillus subtilis Spore Coat

2000 ◽  
Vol 182 (7) ◽  
pp. 1828-1833 ◽  
Author(s):  
Amanda J. Ozin ◽  
Adriano O. Henriques ◽  
Hong Yi ◽  
Charles P. Moran
Keyword(s):  
Bacillus Subtilis ◽  
Modular Design ◽  
Early Stage ◽  
Multilayered Structure ◽  
Terminal Region ◽  
Immunogold Electron Microscopy ◽  
Spore Coat ◽  
Coat Proteins ◽  
Bacillus Subtilis Spore ◽  
Cell Extracts

ABSTRACT During endospore formation in Bacillus subtilis, over two dozen polypeptides are assembled into a multilayered structure known as the spore coat, which protects the cortex peptidoglycan (PG) and permits efficient germination. In the initial stages of coat assembly a protein known as CotE forms a ring around the forespore. A second morphogenetic protein, SpoVID, is required for maintenance of the CotE ring during the later stages, when most of proteins are assembled into the coat. Here, we report on a protein that appears to associate with SpoVID during the early stage of coat assembly. This protein, which we call SafA for SpoVID-associated factor A, is encoded by a locus previously known as yrbA. We confirmed the results of a previous study that showed safA mutant spores have defective coats which are missing several proteins. We have extended these studies with the finding that SafA and SpoVID were coimmunoprecipitated by anti-SafA or anti-SpoVID antiserum from whole-cell extracts 3 and 4 h after the onset of sporulation. Therefore, SafA may associate with SpoVID during the early stage of coat assembly. We used immunogold electron microscopy to localize SafA and found it in the cortex, near the interface with the coat in mature spores. SafA appears to have a modular design. The C-terminal region of SafA is similar to those of several inner spore coat proteins. The N-terminal region contains a sequence that is conserved among proteins that associate with the cell wall. This motif in the N-terminal region may target SafA to the PG-containing regions of the developing spore.

scholarly journals Alternative Translation Initiation Produces a Short Form of a Spore Coat Protein in Bacillus subtilis

2001 ◽  
Vol 183 (6) ◽  
pp. 2032-2040 ◽  
Author(s):  
Amanda J. Ozin ◽  
Teresa Costa ◽  
Adriano O. Henriques ◽  
Charles P. Moran
Keyword(s):  
Bacillus Subtilis ◽  
Translation Initiation ◽  
Stop Codon ◽  
Short Form ◽  
Mature Spore ◽  
Multilayered Structure ◽  
Full Length ◽  
Spore Coat ◽  
Single Transcript ◽  
Spore Coat Protein

ABSTRACT During endospore formation in Bacillus subtilis,over two dozen polypeptides are localized to the developing spore and coordinately assembled into a thick multilayered structure called the spore coat. Assembly of the coat is initiated by the expression of morphogenetic proteins SpoIVA, CotE, and SpoVID. These morphogenetic proteins appear to guide the assembly of other proteins into the spore coat. For example, SpoVID forms a complex with the SafA protein, which is incorporated into the coat during the early stages of development. At least two forms of SafA are found in the mature spore coat: a full-length form and a shorter form (SafA-C30) that begins with a methionine encoded by codon 164 of safA. In this study, we present evidence that the expression of SafA-C30arises from translation initiation at codon 164. We found only a single transcript driving expression of SafA. A stop codon engineered just upstream of a predicted ribosome-binding site near codon M164 abolished formation of full-length SafA, but not SafA-C30. The same effect was observed with an alanine substitution at codon 1 of SafA. Accumulation of SafA-C30 was blocked by substitution of an alanine codon at codon 164, but not by a substitution at a nearby methionine at codon 161. We found that overproduction of SafA-C30 interfered with the activation of late mother cell-specific transcription and caused a strong sporulation block.

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.

Brain Tumor Detection via Asymmetry Quantification across Mid Sagittal Plane

2020 ◽  
Vol 13 ◽  
Author(s):  
Shoaib Amin Banday ◽  
Mohammad Khalid Pandit
Keyword(s):  
Brain Tumor ◽  
Brain Tumors ◽  
Sagittal Plane ◽  
Early Stage ◽  
Imaging Techniques ◽  
Complex Structure ◽  
Magnetic Resonance Images ◽  
Absolute Difference ◽  
Brain Hemispheres ◽  
The Brain

Introduction: Brain tumor is among the major causes of morbidity and mortality rates worldwide. According to National Brain Tumor Foundation (NBTS), the death rate has nearly increased by as much as 300% over last couple of decades. Tumors can be categorized as benign (non-cancerous) and malignant (cancerous). The type of the brain tumor significantly depends on various factors like the site of its occurrence, its shape, the age of the subject etc. On the other hand, Computer Aided Detection (CAD) has been improving significantly in recent times. The concept, design and implementation of these systems ascend from fairly simple ones to computationally intense ones. For efficient and effective diagnosis and treatment plans in brain tumor studies, it is imperative that an abnormality is detected at an early stage as it provides a little more time for medical professionals to respond. The early detection of diseases has predominantly been possible because of medical imaging techniques developed from past many decades like CT, MRI, PET, SPECT, FMRI etc. The detection of brain tumors however, has always been a challenging task because of the complex structure of the brain, diverse tumor sizes and locations in the brain. Method: This paper proposes an algorithm that can detect the brain tumors in the presence of the Radio-Frequency (RF) inhomoginiety. The algorithm utilizes the Mid Sagittal Plane as a landmark point across which the asymmetry between the two brain hemispheres is estimated using various intensity and texture based parameters. Result: The results show the efficacy of the proposed method for the detection of the brain tumors with an acceptable detection rate. Conclusion: In this paper, we have calculated three textural features from the two hemispheres of the brain viz: Contrast (CON), Entropy (ENT) and Homogeneity (HOM) and three parameters viz: Root Mean Square Error (RMSE), Correlation Co-efficient (CC), and Integral of Absolute Difference (IAD) from the intensity distribution profiles of the two brain hemispheres to predict any presence of the pathology. First a Mid Sagittal Plane (MSP) is obtained on the Magnetic Resonance Images that virtually divides brain into two bilaterally symmetric hemispheres. The block wise texture asymmetry is estimated for these hemispheres using the above 6 parameters.

scholarly journals Laccase and Its Mutant Displayed on the Bacillus subtilis Spore Coat for Oxidation of Phenolic Compounds in Organic Solvents

Catalysts ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 606
Author(s):  
Silu Sheng ◽  
Edgardo T. Farinas
Keyword(s):  
Bacillus Subtilis ◽  
Organic Solvents ◽  
Environmental Changes ◽  
Sinapic Acid ◽  
Product Yield ◽  
Spore Coat ◽  
Subtilis Spore ◽  
Bacillus Subtilis Spore ◽  
Cota Laccase ◽  
Inert Surface

Enzymes displayed on the Bacillus subtilis spore coat have several features that are useful for biocatalysis. The enzyme is preimmobilized on an inert surface of the spore coat, which is due to the natural sporulation process. As a result, protein stability can be increased, and they are resistant to environmental changes. Next, they would not lyse under extreme conditions, such as in organic solvents. Furthermore, they can be easily removed from the reaction solution and reused. The laboratory evolved CotA laccase variant T480A-CotA was used to oxidize the following phenolic substrates: (+)-catechin, (−)-epicatechin, and sinapic acid. The kinetic parameters were determined and T480A-CotA had a greater Vmax/Km than wt-CotA for all substrates. The Vmax/Km for T480A-CotA was 4.1, 5.6, and 1.4-fold greater than wt-CotA for (+)-catechin, (−)-epicatechin, and sinapic acid, respectively. The activity of wt-CotA and T480A-CotA was measured at different concentrations from 0–70% in organic solvents (dimethyl sulfoxide, ethanol, methanol, and acetonitrile). The Vmax for T480A-CotA was observed to be greater than the wt-CotA in all organic solvents. Finally, the T480A-CotA was recycled 7 times over a 23-h period and up to 60% activity for (+)-catechin remained. The product yield was up to 3.1-fold greater than the wild-type.

scholarly journals Localization of the Transglutaminase Cross-Linking Sites in the Bacillus subtilis Spore Coat Protein GerQ

2006 ◽  
Vol 188 (21) ◽  
pp. 7609-7616 ◽  
Author(s):  
Alicia Monroe ◽  
Peter Setlow
Keyword(s):  
Bacillus Subtilis ◽  
Coat Protein ◽  
Cross Linking ◽  
Spore Coat ◽  
Bacillus Subtilis Spore ◽  
Binding Partners ◽  
Lysine Residues ◽  
Cross Links ◽  
Hydrolysis Of ◽  
Spore Coat Protein

ABSTRACT The Bacillus subtilis spore coat protein GerQ is necessary for the proper localization of CwlJ, an enzyme important in the hydrolysis of the peptidoglycan cortex during spore germination. GerQ is cross-linked into high-molecular-mass complexes in the spore coat late in sporulation, and this cross-linking is largely due to a transglutaminase. This enzyme forms an ε-(γ-glutamyl) lysine isopeptide bond between a lysine donor from one protein and a glutamine acceptor from another protein. In the current work, we have identified the residues in GerQ that are essential for transglutaminase-mediated cross-linking. We show that GerQ is a lysine donor and that any one of three lysine residues near the amino terminus of the protein (K2, K4, or K5) is necessary to form cross-links with binding partners in the spore coat. This leads to the conclusion that all Tgl-dependent GerQ cross-linking takes place via these three lysine residues. However, while the presence of any of these three lysine residues is essential for GerQ cross-linking, they are not essential for the function of GerQ in CwlJ localization.

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