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.

Ultrastructure of teliospore formation in the rust fungus Puccinia podophylli

1979 ◽  
Vol 57 (22) ◽  
pp. 2533-2538 ◽  
Author(s):  
Charles W. Mims ◽  
E. Laurence Thurston
Keyword(s):  
Rust Fungus ◽  
Ultrastructural Level ◽  
Spore Wall ◽  
Dense Layer ◽  
Spore Surface ◽  
Outer Electron ◽  
Cytoplasmic Material

Teliospore initials of Puccinia podophylli develop from binucleate sporogenous cells lining the base of the telium. The teliospores are formed in basically the same fashion as those of other rusts that have been examined at the ultrastructural level. The long, straight or slightly curved spines present on mature teliospores initially develop as slight bulges or protrusions on the spore surface. The spore wall in such a region then evaginates to form a slender spine that is initially filled with cytoplasm. The cytoplasmic material is then progressively excluded from the tip of the spine as a result of the thickening of the spine wall. Mature teliospores of P. podophylli possess a wall consisting of a thick, outer, electron-dense layer in which stratification is only rarely visible and an inner thinner, less electron-dense layer.

scholarly journals Bacillus subtilis Spore Coat

1999 ◽  
Vol 63 (1) ◽  
pp. 1-20 ◽  
Author(s):  
Adam Driks
Keyword(s):  
Bacillus Subtilis ◽  
Posttranslational Processing ◽  
Spore Coat ◽  
Coat Proteins ◽  
Spore Surface ◽  
Subtilis Spore ◽  
Cell Type ◽  
Dormant Cell ◽  
Bacillus Subtilis Spore ◽  
Specialized Program

SUMMARY In response to starvation, bacilli and clostridia undergo a specialized program of development that results in the production of a highly resistant dormant cell type known as the spore. A proteinacious shell, called the coat, encases the spore and plays a major role in spore survival. The coat is composed of over 25 polypeptide species, organized into several morphologically distinct layers. The mechanisms that guide coat assembly have been largely unknown until recently. We now know that proper formation of the coat relies on the genetic program that guides the synthesis of spore components during development as well as on morphogenetic proteins dedicated to coat assembly. Over 20 structural and morphogenetic genes have been cloned. In this review, we consider the contributions of the known coat and morphogenetic proteins to coat function and assembly. We present a model that describes how morphogenetic proteins direct coat assembly to the specific subcellular site of the nascent spore surface and how they establish the coat layers. We also discuss the importance of posttranslational processing of coat proteins in coat morphogenesis. Finally, we review some of the major outstanding questions in the field.

scholarly journals Characterization of a Major Bacillus anthracis Spore Coat Protein and Its Role in Spore Inactivation

2004 ◽  
Vol 186 (8) ◽  
pp. 2413-2417 ◽  
Author(s):  
Ho-San Kim ◽  
D. Sherman ◽  
F. Johnson ◽  
A. I. Aronson
Keyword(s):  
Coat Protein ◽  
Bacillus Anthracis ◽  
Spore Coat ◽  
Wild Type ◽  
Gene Encoding ◽  
Promising Target ◽  
Section Electron ◽  
Group A ◽  
Dark Staining ◽  
Spore Coat Protein

ABSTRACT A major Bacillus anthracis spore coat protein of 13.4 kDa, designated Cotα, was found only in the Bacillus cereus group. A stable ca. 30-kDa dimer of this protein was also present in spore coat extracts. Cotα, which is encoded by a monocistronic gene, was first detected late in sporulation, consistent with a σK-regulated gene. On the basis of immunogold labeling, the protein is in the outer spore coat and absent from the exosporium. In addition, disruption of the gene encoding Cotα resulted in spores lacking a dark-staining outer spore coat in thin-section electron micrographs. The mutant spores were stable upon heating or storage, germinated at the same rate as the wild type, and were resistant to lysozyme. They were, however, more sensitive than the wild type to phenol, chloroform, and hypochlorite but more resistant to diethylpyrocarbonate. In all cases, resistance or sensitivity to these reagents was restored by introducing a clone of the cotα gene into the mutant. Since Cotα is an abundant outer spore coat protein of the B. cereus group with a prominent role in spore resistance and sensitivity, it is a promising target for the inactivation of B. anthracis spores.

scholarly journals CotA of Bacillus subtilis Is a Copper-Dependent Laccase

2001 ◽  
Vol 183 (18) ◽  
pp. 5426-5430 ◽  
Author(s):  
Marie-Françoise Hullo ◽  
Ivan Moszer ◽  
Antoine Danchin ◽  
Isabelle Martin-Verstraete
Keyword(s):  
Bacillus Subtilis ◽  
Coat Protein ◽  
Uv Light ◽  
Specific Substrate ◽  
Spore Coat ◽  
Wild Type ◽  
Multicopper Oxidases ◽  
Spore Pigment ◽  
Spore Coat Protein

ABSTRACT The spore coat protein CotA of Bacillus subtilisdisplays similarities with multicopper oxidases, including manganese oxidases and laccases. B. subtilis is able to oxidize manganese, but neither CotA nor other sporulation proteins are involved. We demonstrate that CotA is a laccase. Syringaldazine, a specific substrate of laccases, reacted with wild-type spores but not with ΔcotA spores. CotA may participate in the biosynthesis of the brown spore pigment, which appears to be a melanin-like product and to protect against UV light.

scholarly journals Interactions of Bacillus subtilis Basement Spore Coat Layer Proteins

2021 ◽  
Vol 9 (2) ◽  
pp. 285
Author(s):  
Daniela Krajčíková ◽  
Veronika Bugárová ◽  
Imrich Barák
Keyword(s):  
Bacillus Subtilis ◽  
Alanine Racemase ◽  
Spore Coat ◽  
Coat Proteins ◽  
Spore Surface ◽  
Penicillin Binding Protein ◽  
Wild Type ◽  
Protective Layers ◽  
Wet Heat ◽  
Coat Layer

Bacillus subtilis endospores are exceptionally resistant cells encircled by two protective layers: a petidoglycan layer, termed the cortex, and the spore coat, a proteinaceous layer. The formation of both structures depends upon the proper assembly of a basement coat layer, which is composed of two proteins, SpoIVA and SpoVM. The present work examines the interactions of SpoIVA and SpoVM with coat proteins recruited to the spore surface during the early stages of coat assembly. We showed that the alanine racemase YncD associates with two morphogenetic proteins, SpoIVA and CotE. Mutant spores lacking the yncD gene were less resistant against wet heat and germinated to a greater extent than wild-type spores in the presence of micromolar concentrations of l-alanine. In seeking a link between the coat and cortex formation, we investigated the interactions between SpoVM and SpoIVA and the proteins essential for cortex synthesis and found that SpoVM interacts with a penicillin-binding protein, SpoVD, and we also demonstrated that SpoVM is crucial for the proper localization of SpoVD. This study shows that direct contacts between coat morphogenetic proteins with a complex of cortex-synthesizing proteins could be one of the tools by which bacteria couple cortex and coat formation.

scholarly journals Role of collagen-like protein BclA3 in the assembly of the exosporium layer of Clostridioides difficile spores.

2021 ◽  
Author(s):  
Marjorie Pizarro-Guajardo ◽  
Cesar Ortega-Lizarraga ◽  
Ana Inostroza-Mora ◽  
Francisca Cid-Rojas ◽  
Daniel Paredes-Sabja
Keyword(s):  
Immunogold Labelling ◽  
Sigma Factors ◽  
Surface Proteins ◽  
Dense Layer ◽  
Spore Surface ◽  
Wild Type ◽  
Susceptible Host ◽  
Clostridioides Difficile ◽  
In The Wild

Newly formed spores are essential for persistence of C. difficile in the host, transmission to a new susceptible host (Deakin et al., 2012b) and recurrence of CDI. BclA3 and BclA2 Spore surface proteins are expressed during sporulation under the control of mother-cell specific sigma factors of the RNA polymerase, SigE and SigK. Deletion of bclA3 leads to spores with an electron-dense exosporium layer that lacks bump-like structures in the electron-dense layer and hair-like projections, both structures typically found in the wild type spore. Therefore, in this work, we have addressed the role of the exosporium collagen-like BclA3 glycoprotein in the assembly of the exosporium layer. Immunogold labelling of BclA2CTD and BclA3CTD indicates that both proteins are located in the hairs, with BclA2 located outermost of BclA3. Absence of BclA3 leads to spores with no hair-like projections, and absence of bumps in thick exosporium spores, a phenotype also expressed in by the deletion of the collagen-like region of BclA3. Overall, these results provide insights into the role of BclA3 in the assembly of the exosporium layer of C. difficile spores.

Ultrastructure and development of urediospore ornamentation in Melampsora lini

1971 ◽  
Vol 49 (12) ◽  
pp. 2067-2073 ◽  
Author(s):  
L. J. Littlefield ◽  
C. E. Bracker
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Outer Surface ◽  
Spore Wall ◽  
Wall Material ◽  
Wild Type ◽  
Melampsora Lini ◽  
Inner Surface ◽  
External Position ◽  
Basal Portion

The urediospores of Melampsora lini (Ehrenb.) Lev. are echinulate, with spines ca. 1 μ long over their surface. The spines are electron-transparent, conical projections, with their basal portion embedded in the electron-dense spore wall. The entire spore, including the spines, is covered by a wrinkled pellicle ca. 150–200 Å thick. The spore wall consists of three recognizable layers in addition to the pellicle. Spines form initially as small deposits at the inner surface of the spore wall adjacent to the plasma membrane. Endoplasmic reticulum occurs close to the plasma membrane in localized areas near the base of spines. During development, the spore wall thickens, and the spines increase in size. Centripetal growth of the wall encases the spines in the wall material. The spines progressively assume a more external position in the spore wall and finally reside at the outer surface of the wall. A mutant strain with finely verrucose spores was compared to the wild type. The warts on the surface of the mutant spores are rounded, electron-dense structures ca. 0.2–0.4 μ high, in contrast to spines of the wild type. Their initiation near the inner surface of the spore wall and their eventual placement on the outer surface of the spore are similar to that of spines. The wall is thinner in mutant spores than in wild-type spores.

scholarly journals SpoVID Guides SafA to the Spore Coat inBacillus subtilis

2001 ◽  
Vol 183 (10) ◽  
pp. 3041-3049 ◽  
Author(s):  
Amanda J. Ozin ◽  
Craig S. Samford ◽  
Adriano O. Henriques ◽  
Charles P. Moran
Keyword(s):  
Direct Interaction ◽  
Spore Coat ◽  
Coat Proteins ◽  
Yeast Two Hybrid System ◽  
Spore Coat Proteins ◽  
Basement Layer ◽  
Two Hybrid ◽  
Spore Coat Protein

ABSTRACT Bacteria assemble complex structures by targeting proteins to specific subcellular locations. The protein coat that encasesBacillus subtilis spores is an example of a structure that requires coordinated targeting and assembly of more than 24 polypeptides. The earliest stages of coat assembly require the action of three morphogenetic proteins: SpoIVA, CotE, and SpoVID. In the first steps, a basement layer of SpoIVA forms around the surface of the forespore, guiding the subsequent positioning of a ring of CotE protein about 75 nm from the forespore surface. SpoVID localizes near the forespore membrane where it functions to maintain the integrity of the CotE ring and to anchor the nascent coat to the underlying spore structures. However, it is not known which spore coat proteins interact directly with SpoVID. In this study we examined the interaction between SpoVID and another spore coat protein, SafA, in vivo using the yeast two-hybrid system and in vitro. We found evidence that SpoVID and SafA directly interact and that SafA interacts with itself. Immunofluorescence microscopy showed that SafA localized around the forespore early during coat assembly and that this localization of SafA was dependent on SpoVID. Moreover, targeting of SafA to the forespore was also dependent on SpoIVA, as was targeting of SpoVID to the forespore. We suggest that the localization of SafA to the spore coat requires direct interaction with SpoVID.

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