Ultrastructure and cell division of an oral bacterium resembling Alysiella filiformis

1973 ◽  
Vol 19 (3) ◽  
pp. 325-327 ◽  
Author(s):  
Gary E. Kaiser ◽  
Marvin J. Starzyk
Keyword(s):  
Cell Wall ◽  
Cell Division ◽  
Epithelial Cells ◽  
Oral Cavity ◽  
Structural Study ◽  
Cell Separation ◽  
Septum Formation ◽  
Innermost Layer ◽  
Oral Bacterium

Alysiella filiformis is commonly found on the epithelial cells of the oral cavity in rabbits. An ultra-structural study of these cells has shown A. filiformis attached by numerous slime appendages (setae) to the host epithelial cells. The organism possesses a multilayered cell wall 18–22 nm thick. Cell division occurs by constriction of the cytoplasm with concurrent septum formation initiating from the dense innermost layer of the cell wall. This is followed by thickening and delamination of the septum with subsequent invagination of the outer layers of the cell wall causing a partial cell separation. However, the cells of the typical trichomes are still held together by septal bridges. Mesosome-like structures were occasionally found and were often in the area of septum formation. All attempts to culture this organism in vitro were unsuccessful.

scholarly journals The SPOR Domain, a Widely Conserved Peptidoglycan Binding Domain That Targets Proteins to the Site of Cell Division

2017 ◽  
Vol 199 (14) ◽  
Author(s):  
Atsushi Yahashiri ◽  
Matthew A. Jorgenson ◽  
David S. Weiss
Keyword(s):  
Cell Wall ◽  
Cell Division ◽  
Protein Interactions ◽  
Cell Separation ◽  
Protein Protein Interactions ◽  
Target Proteins ◽  
Bacterial Proteins ◽  
Binding Domains ◽  
Division Site ◽  
Daughter Cell Separation

ABSTRACT Sporulation-related repeat (SPOR) domains are small peptidoglycan (PG) binding domains found in thousands of bacterial proteins. The name “SPOR domain” stems from the fact that several early examples came from proteins involved in sporulation, but SPOR domain proteins are quite diverse and contribute to a variety of processes that involve remodeling of the PG sacculus, especially with respect to cell division. SPOR domains target proteins to the division site by binding to regions of PG devoid of stem peptides (“denuded” glycans), which in turn are enriched in septal PG by the intense, localized activity of cell wall amidases involved in daughter cell separation. This targeting mechanism sets SPOR domain proteins apart from most other septal ring proteins, which localize via protein-protein interactions. In addition to SPOR domains, bacteria contain several other PG-binding domains that can exploit features of the cell wall to target proteins to specific subcellular sites.

scholarly journals Surface Display of the Receptor-Binding Region of the Lactobacillusbrevis S-Layer Protein in Lactococcuslactis Provides Nonadhesive Lactococci with the Ability To Adhere to Intestinal Epithelial Cells

2003 ◽  
Vol 69 (4) ◽  
pp. 2230-2236 ◽  
Author(s):  
Silja Åvall-Jääskeläinen ◽  
Agneta Lindholm ◽  
Airi Palva
Keyword(s):  
Cell Wall ◽  
Lactic Acid ◽  
Epithelial Cells ◽  
Lactic Acid Bacterium ◽  
Receptor Binding ◽  
Surface Display ◽  
Intestinal Epithelial ◽  
Binding Region ◽  
Receptor Binding Region

ABSTRACT Lactobacillus brevis is a promising lactic acid bacterium for use as a probiotic dietary adjunct and a vaccine vector. The N-terminal region of the S-layer protein (SlpA) of L. brevis ATCC 8287 was recently shown to mediate adhesion to various human cell lines in vitro. In this study, a surface display cassette was constructed on the basis of this SlpA receptor-binding domain, a proteinase spacer, and an autolysin anchor. The cassette was expressed under control of the nisA promoter in Lactococcus lactis NZ9000. Western blot assay of lactococcal cell wall extracts with anti-SlpA antibodies confirmed that the SlpA adhesion domain of the fusion protein was expressed and located within the cell wall layer. Whole-cell enzyme-linked immunosorbent assay and immunofluorescence microscopy verified that the SlpA adhesion-mediating region was accessible on the lactococcal cell surface. In vitro adhesion assays with the human intestinal epithelial cell line Intestine 407 indicated that the recombinant lactococcal cells had gained an ability to adhere to Intestine 407 cells significantly greater than that of wild-type L. lactis NZ9000. Serum inhibition assay further confirmed that adhesion of recombinant lactococci to Intestine 407 cells was indeed mediated by the N terminus-encoding part of the slpA gene. The ability of the receptor-binding region of SlpA to adhere to fibronectin was also confirmed with this lactococcal surface display system. These results show that, with the aid of the receptor-binding region of the L. brevis SlpA protein, the ability to adhere to gut epithelial cells can indeed be transferred to another, nonadhesive, lactic acid bacterium.

scholarly journals Modification of cell wall polysaccharide spatially controls cell division in Streptococcus mutans

2020 ◽  
Author(s):  
Svetlana Zamakhaeva ◽  
Catherine T. Chaton ◽  
Jeffrey S. Rush ◽  
Sowmya Ajay Castro ◽  
Alexander E. Yarawsky ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Division ◽  
Streptococcus Mutans ◽  
Cell Separation ◽  
Ring Structure ◽  
Cell Wall Polysaccharide ◽  
Bacterial Cell Division ◽  
Glycerol Phosphate ◽  
Immature Form ◽  
Z Ring

AbstractBacterial cell division is driven by a tubulin homolog FtsZ, which assembles into the Z-ring structure leading to the recruitment of the cell division machinery. In ovoid-shaped Gram-positive bacteria, such as streptococci, MapZ guides Z-ring positioning at cell equators through an, as yet, unknown mechanism. The cell wall of the important dental pathogen Streptococcus mutans is composed of peptidoglycan decorated with Serotype c Carbohydrates (SCCs). Here, we show that an immature form of SCC, lacking the recently identified glycerol phosphate (GroP) modification, coordinates Z-ring positioning. Pulldown assays using S. mutans cell wall combined with binding affinity analysis identified the major cell separation autolysin, AtlA, as an SCC binding protein. Importantly, AtlA binding to mature SCC is attenuated due to GroP modification. Using fluorescently-labeled AtlA, we mapped SCC distribution on the streptococcal surface to reveal that GroP-deficient immature SCCs are exclusively present at the cell poles and equators. Moreover, the equatorial GroP-deficient SCCs co-localize with MapZ throughout the S. mutans cell cycle. Consequently, in GroP-deficient mutant bacteria, proper AtlA localization is abrogated resulting in dysregulated cellular autolysis. In addition, these mutants display morphological abnormalities associated with MapZ mislocalization leading to Z-ring misplacement. Altogether, our data support a model in which GroP-deficient immature SCCs spatially coordinate the localization of AtlA and MapZ. This mechanism ensures cell separation by AtlA at poles and Z-ring alignment with the cell equator.Graphical abstract

scholarly journals FtsW exhibits distinct processive motions driven by either septal cell wall synthesis or FtsZ treadmilling in E. coli

2019 ◽  
Author(s):  
Xinxing Yang ◽  
Ryan McQuillen ◽  
Zhixin Lyu ◽  
Polly Phillips-Mason ◽  
Ana De La Cruz ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Division ◽  
Single Molecule ◽  
Bacterial Cell ◽  
Spatial Information ◽  
Bacterial Species ◽  
E Coli ◽  
Slow Moving

AbstractDuring bacterial cell division, synthesis of new septal peptidoglycan (sPG) is crucial for successful cytokinesis and cell pole morphogenesis. FtsW, a SEDS (Shape, Elongation, Division and Sporulation) family protein and an indispensable component of the cell division machinery in all walled bacterial species, was recently identified in vitro as a new monofunctional peptidoglycan glycosyltransferase (PGTase). FtsW and its cognate monofunctional transpeptidase (TPase) class B penicillin binding protein (PBP3 or FtsI in E. coli) may constitute the essential, bifunctional sPG synthase specific for new sPG synthesis. Despite its importance, the septal PGTase activity of FtsW has not been documented in vivo. How its activity is spatiotemporally regulated in vivo has also remained unknown. Here we investigated the septal PGTase activity and dynamics of FtsW in E. coli cells using a combination of single-molecule imaging and genetic manipulations. We show that FtsW exhibits robust activity to incorporate an N-acetylmuramic acid analog at septa in the absence of other known PGTases, confirming FtsW as the essential septum-specific PGTase in vivo. Notably, we identified two populations of processive moving FtsW molecules at septa. A fast-moving population is driven by the treadmilling dynamics of FtsZ and independent of sPG synthesis. A slow-moving population is driven by active sPG synthesis and independent of FtsZ’s treadmilling dynamics. We further identified that FtsN, a potential sPG synthesis activator, plays an important role in promoting the slow-moving, sPG synthesis-dependent population. Our results support a two-track model, in which inactive sPG synthase molecules follow the fast treadmilling “Z-track” to be distributed along the septum; FtsN promotes their release from the “Z-track” to become active in sPG synthesis on the slow “sPG-track”. This model explains how the spatial information is integrated into the regulation of sPG synthesis activity and suggests a new mechanistic framework for the spatiotemporal coordination of bacterial cell wall constriction.

scholarly journals Dynamic localisation of DamX regulates bacterial filamentation and division during UPEC dispersal from host cells

2021 ◽  
Author(s):  
Bill Soderstrom ◽  
Daniel O. Daley ◽  
Iain G. Duggin
Keyword(s):  
Escherichia Coli ◽  
Cell Division ◽  
Stress Response ◽  
Epithelial Cells ◽  
Membrane Fusion ◽  
Host Cells ◽  
Division Rings ◽  
Bladder Cells ◽  
Rod Cell

Uropathogenic Escherichia coli (UPEC) cells can grow into highly filamentous forms during infection of bladder epithelial cells, but this process is poorly understood. Herein we found that some UPEC filaments released from infected bladder cells in vitro grew very rapidly and by more than 100 μm before initiating division, whereas others did not survive, suggesting that filamentation is a stress response that promotes dispersal. The DamX bifunctional division protein, which is essential for UPEC filamentation, was initially non-localized but then assembled at multiple division sites in the filaments prior to division. DamX rings maintained consistent thickness during constriction and remained at the septum until after membrane fusion was completed, like in rod cell division. Our findings suggest a mechanism involving regulated dissipation of DamX, leading to division arrest and filamentation, followed by its reassembly into division rings to promote UPEC dispersal and survival during infection.

Study of Adhesion of Lactobacillus casei CRL 431 to Ileal Intestinal Cells of Mice

1999 ◽  
Vol 62 (12) ◽  
pp. 1430-1434 ◽  
Author(s):  
VILMA I. MORATA de AMBROSINI ◽  
SILVIA N. GONZALEZ ◽  
G. OLIVER
Keyword(s):  
Cell Wall ◽  
Immune System ◽  
Epithelial Cells ◽  
Lactobacillus Acidophilus ◽  
Lactobacillus Casei ◽  
Intestinal Cells ◽  
Surface Molecules ◽  
Good Ability ◽  
Initial Stage

It is well known that the cell wall of Lactobacillus casei CRL 431, a strain present in probiotics, presents lectinlike surface molecules. Presence of these molecules stimulates the immune system. Given the role that lectins and lectinlike substances play in the adhesion phenomenon, it is probable that this is an initial stage in the immunostimulation produced by this bacterium. To confirm this, adhesion of this microorganism to exfoliated mouse ileal epithelial cells was studied in vitro. Other L. casei strains isolated from adult human intestines and one of dairy origin were also examined for their ability to adhere to ileal epithelial cells. Another strain, which was included in the present study, was Lactobacillus acidophilus CRL 730. L. casei strains isolated from humans showed good ability to adhere to ileal epithelial cells, whereas L. casei isolated from dairy origin did not. Adhesion was only observed at 37°C and at a pH between 6 and 7.5. The exposure time needed for highest adhesion was 30 min. Presence of lectinlike substances on the surface of L. casei CRL 431 is important to this adhesion phenomenon, since adherence capacity was lost after removal of these substances.

scholarly journals Peptidoglycan Hydrolases RipA and Ami1 Are Critical for Replication and Persistence of Mycobacterium tuberculosis in the Host

mBio ◽  
2020 ◽  
Vol 11 (2) ◽  
Author(s):  
Claire Healy ◽  
Alexandre Gouzy ◽  
Sabine Ehrt
Keyword(s):  
Cell Wall ◽  
Mycobacterium Tuberculosis ◽  
Cell Division ◽  
Drug Target ◽  
New Drugs ◽  
Chemotherapeutic Regimen ◽  
Content Type ◽  
Cell Wall Polymer ◽  
Redundant Functions

ABSTRACT Synthesis and cleavage of the cell wall polymer peptidoglycan (PG) are carefully orchestrated processes and are essential for the growth and survival of bacteria. Yet, the function and importance of many enzymes that act on PG in Mycobacterium tuberculosis remain to be elucidated. We demonstrate that the activity of the N-acetylmuramyl-l-alanine amidase Ami1 is dispensable for cell division in M. tuberculosis in vitro yet contributes to the bacterium’s ability to persist during chronic infection in mice. Furthermore, the d,l-endopeptidase RipA, a predicted essential enzyme, is dispensable for the viability of M. tuberculosis but required for efficient cell division in vitro and in vivo. Depletion of RipA sensitizes M. tuberculosis to rifampin and to cell envelope-targeting antibiotics. Ami1 helps sustain residual cell division in cells lacking RipA, but the partial redundancy provided by Ami1 is not sufficient during infection, as depletion of RipA prevents M. tuberculosis from replicating in macrophages and leads to dramatic killing of the bacteria in mice. Notably, RipA is essential for persistence of M. tuberculosis in mice, suggesting that cell division is required during chronic mouse infection. Despite the multiplicity of enzymes acting on PG with redundant functions, we have identified two PG hydrolases that are important for M. tuberculosis to replicate and persist in the host. IMPORTANCE Tuberculosis (TB) is a major global heath burden, with 1.6 million people succumbing to the disease every year. The search for new drugs to improve the current chemotherapeutic regimen is crucial to reducing this global health burden. The cell wall polymer peptidoglycan (PG) has emerged as a very successful drug target in bacterial pathogens, as many currently used antibiotics target the synthesis of this macromolecule. However, the multitude of genes encoding PG-synthesizing and PG-modifying enzymes with apparent redundant functions has hindered the identification of novel drug targets in PG synthesis in Mycobacterium tuberculosis. Here, we demonstrate that two PG-cleaving enzymes are important for virulence of M. tuberculosis. In particular, the d,l-endopeptidase RipA represents a potentially attractive drug target, as its depletion results in the clearance of M. tuberculosis from the host and renders the bacteria hypersusceptible to rifampin, a frontline TB drug, and to several cell wall-targeting antibiotics.

scholarly journals Anti-Inflammatory Properties of Streptococcus salivarius, a Commensal Bacterium of the Oral Cavity and Digestive Tract

2013 ◽  
Vol 80 (3) ◽  
pp. 928-934 ◽  
Author(s):  
Ghalia Kaci ◽  
Denise Goudercourt ◽  
Véronique Dennin ◽  
Bruno Pot ◽  
Joël Doré ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Oral Cavity ◽  
Mononuclear Cells ◽  
Inflammatory Responses ◽  
Intestinal Epithelial Cells ◽  
Intestinal Epithelial ◽  
Streptococcus Salivarius ◽  
Content Type ◽  
Anti Inflammatory

ABSTRACTStreptococcus salivariusis one of the first colonizers of the human oral cavity and gut after birth and therefore may contribute to the establishment of immune homeostasis and regulation of host inflammatory responses. The anti-inflammatory potential ofS. salivariuswas first evaluatedin vitroon human intestinal epithelial cells and human peripheral blood mononuclear cells. We show that liveS. salivariusstrains inhibitedin vitrothe activation of the NF-κB pathway on intestinal epithelial cells. We also demonstrate that the liveS. salivariusJIM8772 strain significantly inhibited inflammation in severe and moderate colitis mouse models. Thesein vitroandin vivoanti-inflammatory properties were not found with heat-killedS. salivarius, suggesting a protective response exclusively with metabolically active bacteria.

scholarly journals Diversification of LytM Protein Functions in Polar Elongation and Cell Division of Agrobacterium tumefaciens

2021 ◽  
Vol 12 ◽  
Author(s):  
Wanda M. Figueroa-Cuilan ◽  
Amelia M. Randich ◽  
Caroline M. Dunn ◽  
Gustavo Santiago-Collazo ◽  
Andrew Yowell ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Division ◽  
Agrobacterium Tumefaciens ◽  
Bacterial Cell ◽  
Cell Separation ◽  
Amide Bonds ◽  
Multiple Partners ◽  
Peptidoglycan Cell Wall ◽  
Protein Functions ◽  
Bacterial Cell Cycle

LytM-domain containing proteins are LAS peptidases (lysostaphin-type enzymes, D-Ala-D-Ala metallopeptidases, and sonic hedgehog) and are known to play diverse roles throughout the bacterial cell cycle through direct or indirect hydrolysis of the bacterial cell wall. A subset of the LytM factors are catalytically inactive but regulate the activity of other cell wall hydrolases and are classically described as cell separation factors NlpD and EnvC. Here, we explore the function of four LytM factors in the alphaproteobacterial plant pathogen Agrobacterium tumefaciens. An LmdC ortholog (Atu1832) and a MepM ortholog (Atu4178) are predicted to be catalytically active. While Atu1832 does not have an obvious function in cell growth or division, Atu4178 is essential for polar growth and likely functions as a space-making endopeptidase that cleaves amide bonds in the peptidoglycan cell wall during elongation. The remaining LytM factors are degenerate EnvC and NlpD orthologs. Absence of these proteins results in striking phenotypes indicative of misregulation of cell division and growth pole establishment. The deletion of an amidase, AmiC, closely phenocopies the deletion of envC suggesting that EnvC might regulate AmiC activity. The NlpD ortholog DipM is unprecedently essential for viability and depletion results in the misregulation of early stages of cell division, contrasting with the canonical view of DipM as a cell separation factor. Finally, we make the surprising observation that absence of AmiC relieves the toxicity induced by dipM overexpression. Together, these results suggest EnvC and DipM may function as regulatory hubs with multiple partners to promote proper cell division and establishment of polarity.

OBSERVATIONS ON THE OVARY CULTURED IN VITRO

1956 ◽  
Vol 14 (2) ◽  
pp. 155-159 ◽  
Author(s):  
D. L. INGRAM
Keyword(s):  
Cell Division ◽  
Epithelial Cells ◽  
Sexual Maturity ◽  
Ovarian Tissue ◽  
Serial Sections ◽  
Foetal Life ◽  
Rats And Mice

SUMMARY The ovaries of rats and mice ranging in age from foetal life to sexual maturity have been cultured and observed in vitro. Structures which had some resemblance to oocytes were seen among the epithelial cells which grew out from the ovarian tissue, but it is concluded that they were not oocytes. No evidence for the neoformation of oocytes was obtained. Serial sections of ovaries, which had been fixed after various periods of culture, were examined for signs of oogenesis. Numerous oocytes in the prophase of cell division were seen in foetal and neonatal material, but not in cultures of adult, or even prepubertal material.

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